U.S. patent application number 15/348191 was filed with the patent office on 2017-05-11 for stator and bldc motor having the same.
The applicant listed for this patent is Johnson Electric S.A.. Invention is credited to Xian Chun FAN, Long Shun JIANG, Yong Bin LI, Ping WANG.
Application Number | 20170133894 15/348191 |
Document ID | / |
Family ID | 58584130 |
Filed Date | 2017-05-11 |
United States Patent
Application |
20170133894 |
Kind Code |
A1 |
LI; Yong Bin ; et
al. |
May 11, 2017 |
Stator and BLDC Motor Having the Same
Abstract
A brushless direct current motor includes a stator and a rotor
rotatable relative to the stator. The stator includes a plurality
of segments arranged circumferentially and a support bracket
connecting the segments together. Each segment includes a segment
core unit and a winding assembly assembled on the segment core
unit. The segment core units of two adjacent segments defining a
gap there between. The support bracket is made of non-magnetic
material.
Inventors: |
LI; Yong Bin; (Hong Kong,
CN) ; JIANG; Long Shun; (Shenzhen, CN) ; FAN;
Xian Chun; (Shenzhen, CN) ; WANG; Ping;
(Shenzhen, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Johnson Electric S.A. |
Murten |
|
CH |
|
|
Family ID: |
58584130 |
Appl. No.: |
15/348191 |
Filed: |
November 10, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02K 3/12 20130101; H02K
1/2706 20130101; H02K 3/34 20130101; H02K 1/14 20130101; H02K 1/165
20130101; H02K 3/325 20130101 |
International
Class: |
H02K 1/16 20060101
H02K001/16; H02K 3/34 20060101 H02K003/34; H02K 1/27 20060101
H02K001/27; H02K 3/12 20060101 H02K003/12 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 10, 2015 |
CN |
2015 1076 0759.4 |
Claims
1. A stator for a motor, comprising: a plurality of segments
arranged circumferentially, each segment comprising a segment core
unit and a winding assembly assembled on the segment core unit, the
segment core units of two adjacent segments defining a gap there
between; and a non-magnetic support bracket connecting the segments
together.
2. The stator of claim 1, wherein the number of the segments is 3N,
where N.gtoreq.1.
3. The stator of claim 1, wherein a portion of the support bracket
is inserted into the gap between the segment core units of the two
adjacent segments.
4. The stator of claim 2, wherein the support bracket comprises an
end plate and a plurality of connecting portions extending from the
end plate, and each connecting portion is inserted into the gap
between the segment core units of two adjacent segments.
5. The stator of claim 4, wherein one of the connecting portion and
the segment core unit forms a latching block, the other of the
connecting portion and the segment core unit forms a latching slot,
and the latching block is engaged in the latching slot to connect
the adjacent segment core units together.
6. The stator of claim 4, wherein each segment core unit forms an
axial hole, the support bracket forms a plurality of mounting
posts, and each mounting post is engaged in the axial hole of a
respective segment core unit.
7. The stator of claim 6, further comprising another support
bracket, the another support bracket comprises an end plate and a
plurality of mounting posts extending from the end plate, and each
mounting post is engaged in the axial hole of a respective segment
core unit.
8. The stator of claim 7, wherein the mounting posts of the another
support bracket are respectively aligned with the mounting posts of
the support bracket.
9. The stator of claim 8, wherein a total length of the two aligned
mounting posts of the support bracket and the another support
bracket is not greater than an axial height of the segment core
unit.
10. The stator of claim 4, wherein the segment core unit is
generally W-shaped, comprising two wing portions and an arm portion
disposed between the two wing portions, the wing portions and the
arm portion define an assembly space there between, and the winding
assembly is attached around the arm portion and disposed in the
assembly space.
11. The stator of claim 10, wherein the support bracket forms a
partition plate extending from the end plate, and the partition
plate is inserted into the assembly space between the arm portion
and a neighboring wing portion to isolate the winding assembly from
the wing portion.
12. The stator of claim 10, wherein each wing portion forms a
latching block, the connecting portion forms corresponding latching
slots, and the latching blocks of the adjacent wing portions of two
neighboring segments are engaged in the latching slots of a
corresponding connecting portion.
13. The stator of claim 10, wherein the winding assembly comprises
an insulating bracket and a winding wound around the insulating
bracket, a central area of the insulating bracket forms an assembly
hole corresponding to the arm portion, the winding assembly is
mounted to the segment core unit with the arm portion of the
segment core unit being inserted into the assembly hole of the
insulating bracket.
14. A brushless direct current motor comprising a stator according
to claim 1 and a rotor rotatable relative to the stator.
15. A stator for a motor, comprising: a plurality of segments
arranged circumferentially, each segment comprising a segment core
unit and a winding assembly assembled on the segment core unit; and
a support bracket connecting the segments together, wherein two
adjacent segments are separated from each other by a portion of the
support bracket.
16. The stator of claim 15, wherein the support bracket comprises a
plurality of mounting post, each segment core unit defines a
through hole therein, and each mounting post is engaged in the
through hole of a respective segment core unit.
17. The stator of claim 15, wherein the portion of the support
bracket and the segment core unit are connected together by a
latching mechanism, and the latching mechanism comprises a latching
slot and a latching block engagable with the latching slot.
18. The armature of claim 15, wherein the segment core unit is
substantially W-shaped, comprising two wing portions and an arm
portion disposed between the two wing portions, the wing portions
and the arm portion define an assembly space there between, and the
winding assembly is attached around the arm portion and located in
the assembly space.
19. The armature of claim 18, wherein the support bracket comprises
a partition plate inserting into the assembly space between the arm
portion and an adjacent wing portion to isolate the winding
assembly from the wing portion.
20. A brushless direct current motor comprising a stator according
to claim 15 and a rotor rotatable relative to the stator.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This non-provisional patent application claims priority
under 35 U.S.C. .sctn.119(a) from Patent Application No.
201510760759.4 filed in The People's Republic of China on 10 Nov.
2015.
FIELD OF THE INVENTION
[0002] The present invention relates to a BLDC motor, and in
particular to a stator and a BLDC motor having the same.
BACKGROUND OF THE INVENTION
[0003] Brushless direct current (BLDC) motors typically include a
stator winding and a permanent magnet rotor. The direction of the
current in the stator winding is altered based on the position of
the rotor, thus establishing an alternating magnetic field which
drives the rotor to continuously rotate. The brushless direct
current motors have long lifespan and low noise.
[0004] The existing BLDC motor overall is usually of a circular
cylindrical structure. The stator includes an annular stator core
and a plurality of teeth extending radially from the stator core.
The teeth are arranged uniformly in a circumferential direction of
the stator core. The winding is wound around the teeth. The rotor
is received in the stator and opposed to the stator. However, the
stator core is of a continuous annular structure, which causes a
certain degree of magnetic leakage such that the magnetic flux and
efficiency is reduced. On the other hand, the annular stator core
also limits a slot opening between the teeth, which makes it
inconvenient to wind the windings and results in a low slot fill
factor.
SUMMARY OF THE INVENTION
[0005] Thus, there is a desire for a stator and a motor having the
same, which can effectively increase the slot fill factor and
magnetic flux and hence the efficiency of the motor.
[0006] In one aspect, a stator is provided which includes a
plurality of segments arranged circumferentially and a support
bracket connecting the segments together. Each segment includes a
segment core unit and a winding assembly assembled on the segment
core unit. The segment core units of two adjacent segments defining
a gap there between. The support bracket is made of non-magnetic
material.
[0007] Preferably, the number of the segments is 3N, where
N.gtoreq.1.
[0008] Preferably, a portion of the support bracket is inserted
into the gap between the segment core units of the two adjacent
segments.
[0009] Preferably, the support bracket comprises an end plate and a
plurality of connecting portions extending from the end plate, and
each connecting portion is inserted into the gap between the
segment core units of two adjacent segments.
[0010] Preferably, one of the connecting portion and the segment
core unit forms a latching block, the other of the connecting
portion and the segment core unit forms a latching slot, and the
latching block is engaged in the latching slot to connect the
adjacent segment core units together.
[0011] Preferably, each segment core unit forms an axial hole, the
support bracket forms a plurality of mounting posts, and each
mounting post is engaged in the axial hole of a respective segment
core unit.
[0012] Preferably, the stator further includes another support
bracket, the another support bracket comprises an end plate and a
plurality of mounting posts extending from the end plate, and each
mounting post is engaged in the axial hole of a respective segment
core unit.
[0013] Preferably, the mounting posts of the another support
bracket are respectively aligned with the mounting posts of the
support bracket.
[0014] Preferably, a total length of the two aligned mounting posts
of the support bracket and the another support bracket is not
greater than an axial height of the segment core unit.
[0015] Preferably, the segment core unit is generally W-shaped,
comprising two wing portions and an arm portion disposed between
the two wing portions, the wing portions and the arm portion define
an assembly space there between, and the winding assembly is
attached around the arm portion and disposed in the assembly
space.
[0016] Preferably, the support bracket forms a partition plate
extending from the end plate, and the partition plate is inserted
into the assembly space between the arm portion and a neighboring
wing portion to isolate the winding assembly from the wing
portion.
[0017] Preferably, each wing portion forms a latching block, the
connecting portion forms corresponding latching slots, and the
latching blocks of the adjacent wing portions of two neighboring
segments are engaged in the latching slots of a corresponding
connecting portion.
[0018] Preferably, the winding assembly comprises an insulating
bracket and a winding wound around the insulating bracket, a
central area of the insulating bracket forms an assembly hole
corresponding to the arm portion, the winding assembly is mounted
to the segment core unit with the arm portion of the segment core
unit being inserted into the assembly hole of the insulating
bracket.
[0019] In another aspect, another stator is provided which includes
a plurality of segments arranged circumferentially and a support
bracket connecting the segments together. Each segment includes a
segment core unit and a winding assembly assembled on the segment
core unit. Two adjacent segments are separated from each other by a
portion of the support bracket.
[0020] In another aspect, a brushless direct current motor is
provided which includes the above stator and a rotor rotatable
relative to the stator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 illustrates a brushless direct current motor
according to one embodiment of the present invention.
[0022] FIG. 2 illustrates a stator of the motor of FIG. 1.
[0023] FIG. 3 is an exploded view of the stator of FIG. 2.
[0024] FIG. 4 is an exploded view of the stator, viewed from
another aspect.
[0025] FIG. 5 illustrates an individual segment of the armature of
the stator.
[0026] FIG. 6 is an exploded view of the armature segment of FIG.
5.
[0027] FIG. 7 is a cross sectional view of the stator.
[0028] FIG. 8 illustrates a rotor of the motor of FIG. 1.
[0029] FIG. 9 is a longitudinal cross sectional view of the rotor
of FIG. 8.
[0030] FIG. 10 is a transverse cross-sectional view of the rotor of
FIG. 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] FIG. 1 illustrates a brushless direct current motor
according to one embodiment of the present invention. The brushless
direct current motor includes a stator 10, and a rotor 30 rotatable
relative to the stator 10. In this embodiment, the motor is an
inner-rotor motor, and the rotor 30 is rotatably mounted into the
stator 10.
[0032] Referring to FIG. 2 to FIG. 4, the stator 10 includes an
armature 11, and two support brackets 12 (hereinafter referred as
upper support bracket 12a and lower support bracket 12b) disposed
at two axial ends of the armature 11. The armature 11 is of a
segmented structure including a plurality of segments 13. The
number of the segments 13 is 3N, wherein N is an integer equal or
greater than 1, i.e., N.gtoreq.1. Preferably, the segments 13 of
the armature 11 are substantially of the same structure and evenly
arranged along a circumferential direction. Adjacent segments 13
define a gap 14 there between, i.e. the segments 13 are
discontinuously arranged in the circumferential direction. In this
embodiment, the armature 11 includes three segments 13 and the
overall outer shape of the armature 11 is generally a triangle. A
circular through hole 15 is cooperatively defined by the three
segments 13, and the rotor 30 is received in the through hole 15.
As such, the overall outer shape of the assembled motor is
substantially triangle-shaped.
[0033] In an alternative embodiment, based on the number of the
segments 13, the outer shape of the motor/armature 11 is
substantially a polygon with 3N sides. For example, six segments 13
form a motor/armature 11 in the shape of a hexagon, and nine
segments 13 form a motor/armature 11 in the shape of an enneagon.
In comparison with the traditional round or square motor, the
motor/armature 11 in the shape of a polygon with 3N sides can
remove excessive core portions, which reduces the weight and size
of the motor/armature 11 and hence satisfies user's special
requirements for mounting space.
[0034] Referring to FIG. 5 and FIG. 6, each segment 13 of the
armature 11 includes a segment core unit 16 and a winding assembly
17 wound around the segment core unit 16. The segment core unit 16
is formed by stacking a plurality of core laminations such as
silicon steel laminations. The segment core unit 16 overall is in
the shape of W, including two wing portions 18 and an arm portion
19 disposed between the two wing portions 18. Radial outer ends of
the wing portions 18 and the arm portion 19, i.e. the ends at a
radial outer side of the stator 10, are connected together. Radial
inner ends of the wing portions 18 and the arm portion 19, i.e. the
ends facing the rotor 30, are separated apart from each other. Each
wing portion 18 and the arm portion 19 form an assembling space 20
there between, for mounting the winding assembly 17.
[0035] Preferably, each wing portion 18 forms a through hole 21
that axially passes through the wing portion 18. The radial inner
end of each wing portion 18 protrudes radially inwardly to form a
latching block 22 for mounting with the support bracket 12. The
winding assembly 17 includes an insulating bracket 23 and a winding
24 wound around the insulating bracket 23. Preferably, the
insulating bracket 23 is made of insulating plastic. An
electrically conductive pin is fixedly inserted in the insulating
bracket 23. The winding 24 is wound on the insulating bracket 23
and electrically connected with the electrically conductive pin.
The winding assembly 17 is attached around the arm portion 19 of
the segment core unit 16. A central area of the insulating bracket
23 defines an assembly hole 230 corresponding to the arm portion
19.
[0036] The support bracket 12, made of a non-magnetic material such
as insulating plastic, connects the segments 13 of the armature 11
together, with the segment core units 16 of the respective segments
13 separated to reduce magnetic leakage. Referring also to FIG. 3
and FIG. 4, the upper support bracket 12a and the lower support
bracket 12b are similar in construction, both including an end
plate 25 and a plurality of mounting posts 26 extending
perpendicularly from the end plate 25. The end plates 25 are sheets
covering two axial ends of the armature 11, respectively. Each end
plate 25 has an outer shape and a size matching with the armature
11. For example, in this embodiment, each end plate 25 is
substantially triangular, having an internal round hole. The
mounting posts 26 of the upper and lower support brackets 12a, 12b
are aligned with each other in the axial direction. A total length
of each two aligned mounting posts 26 extending out of the end
plates 25 is not greater than an axial height of the segment core
unit 16. As such, after assembled, the aligned mounting posts 26 of
the two support brackets 12a, 12b do not interfere with each other.
The mounting posts 26 correspond to the through holes 21 of the
wing portions 18 of the segment core unit 16. In assembly, each two
axially aligned mounting posts 26 of the two support brackets 12a,
12b are inserted into one same through hole 21 from the two axial
ends of the segment core unit 16, respectively, to position and
support the segment core unit 16.
[0037] The lower support bracket 12b further forms two partition
plates 27 corresponding to each segment 13. The two partition
plates 27 extend perpendicularly from the end plate 25. The length
of the partition plate 27 extending out of the end plate 25 is
substantially equal to the axial height of the segment core unit
16. The lower support bracket 12b further forms a connecting
portion 28 corresponding to each two adjacent segments 13. The
connecting portion 28 extends perpendicularly from the end plate
25. The length of the connecting portion 28 extending out of the
end plate 25 is substantially equal to the axial height of the
segment core unit 16. Preferably, the connecting portion 28 has an
H-shaped cross-section with two latching slots 29 formed at two
sides thereof. Each latching slot 28 engagingly receives one
corresponding latching block 22 of the wing portion 28 of the
segment core unit 16 of one adjacent segment 13.
[0038] Referring also to FIG. 7, during assembly, each partition
plate 27 is inserted into the space 20 between one wing portion 18
and the arm portion 19 of the segment core unit 16 and leans on the
wing portion 18, thus isolating the windings 24 from the wing
portion 18 of the segment core unit 16 to prevent the windings 24
from short circuit. Each connecting portion 28 is inserted into the
gap 14 between the corresponding wing portions 18 of the segment
core units 16 of the adjacent segments 13. The latching blocks 22
of the two wing portions 18 axially slide into the latching slots
29 of the connecting portion 28, respectively, which connects the
adjacent segments 13 together to form the armature 11. Preferably,
the latching block 22 form a dovetail shaped and the latching slot
29 has a shape matching the latching block, thus avoid
disengagement there between. In an alternative embodiment, the
latching block may also be of another shape such as rectangular or
wedge shape, and the latching slot has a shape matching with the
latching block, which can also result in a firm connection.
[0039] In this embodiment, the partition plates 27 are formed on
the lower support bracket 12b to isolate the segment core units 16
from the windings 24, and the connecting portions 28 are formed to
connect the segment core units 16. In another embodiments, the
partition plates 27 may also be formed on the upper support bracket
12a, or both the upper and lower support brackets 12a, 12b are
formed with the partition plates 27. The connecting portions 28 may
be formed on the upper support bracket 12a, or both the upper and
lower support brackets 12a, 12b are formed with the connecting
portions 28. In addition, the connecting portions 28 and the
partition plates 27 may be formed on the same support bracket 12a
or 12b, or formed on the upper and lower bracket 12a and 12b,
respectively.
[0040] Further, in this embodiment, the latching block 22 is formed
on the wing portion 18 of the segment core unit 16, the latching
slot 29 is formed on the connecting portion 28, and the latching
block 22 is engaged in the latching slot 29 to connect two adjacent
segments 13. In an alternative embodiment, the latching slot 29 may
be fruited on the segment core unit 16, the connecting portion 28
is formed with the protruding latching block 22, and the adjacent
segments 13 are likewise connected together through the locking
connection between the latching block and the latching slot. This
locking connection structure is also simple and convenient to
operate.
[0041] During manufacturing of the stator 10, the winding 24 is
first wound on the insulating bracket 23. The winding may be wound
by using a concentrated winding method. After the winding is
completed, the assembly hole 230 of the insulating bracket 23 is
aligned with the arm portion 19 of the segment core unit 16, and
the arm 19 of the segment core unit 16 is pressed into the assembly
hole 230 of the insulating bracket 23, or the insulating bracket 23
is attached around the arm portion 19 to form an individual segment
13 of the armature 11. The upper and lower support brackets 12a,
12b are mounted to the two axial ends of the segments 13 to connect
the segments 13 together to form the stator 10.
[0042] In the present invention, the winding 24 is wound on the
insulating bracket 23 before the insulating bracket 23 is assembled
to the segment core unit 16. Therefore, winding of the winding 24
is not subject to the limit of the shape and size of the slot
opening and the winding process, which can effectively increase the
slot fill factor of the winding 24 and the power density of the
motor. In comparison with the windings directly wound on the
integral segment core unit, the winding process and the assembly
with the segment core unit after the winding process are simple,
fast and highly efficient, which facilitates automation of the
manufacturing process. In addition, the stator 10 is formed by
multiple segments 13 connected together through the support bracket
12, and the segment core units 16 of the stator 10 are isolated by
the non-magnetic connecting portions 28 in the circumferential
direction. In comparison with the traditional integral stator
design, the stator 10 of the present invention reduces the magnetic
leakage on the magnetic path, which increases the motor performance
by at least 10%.
[0043] Referring to FIG. 8 to FIG. 10, the rotor 30 includes a
rotary shaft 32, a rotor core 34 fixedly attached on the rotary
shaft 32, a plurality of magnets 36 attached to the rotor core 34,
and a rotor sleeve 38 surrounding the magnets 36. The rotor core 34
is generally cylindrical. A plurality of grooves 35 are formed in a
radial outer surface of the rotor core 34. The grooves 35 are
uniformly spaced along a circumferential direction. Each groove 35
passes through the rotor core 34 along an axial direction. In this
embodiment, the number of the grooves 35 is ten. Each groove 35
receives one magnet 36 therein. The magnet 36 may be a ferrite
magnet 36. The radial outer surface of the magnet 36 is arc-shaped,
and the radial outer surfaces of all magnets 36 are substantially
located on one same cylindrical surface. In this embodiment, the
outer surface of the magnet 36 protrudes beyond the outer surface
of the rotor core 34. There are two rotor sleeves 38 each being a
cylindrical structure with one open end.
[0044] In assembly, the two rotor sleeves 38 are pressed onto the
rotor core 34 from two axial ends thereof, respectively, radially
surrounding the rotor core 34 and the magnets 36 to prevent the
magnets from falling off during rotating of the rotor. In assembly,
the rotor 30 is inserted into the through hole 15 of the stator 10,
the stator 10 and rotor 30 are directly mounted to a user system.
An mounting housing with flange for the mounting purpose are
integrally formed with a mounting bracket of the user system by
die-casting, which reduces the number of components and the
assembly process thus reducing the material cost and assembly
cost.
[0045] Although the invention is described with reference to one or
more preferred embodiments, it should be appreciated by those
skilled in the art that various modifications are possible. For
example, while the armature is used as the stator in this
embodiment, the armature may also be used as the rotor. Therefore,
the scope of the invention is to be determined by reference to the
claims that follow.
* * * * *